Networks and Wi-Fi
Power over Ethernet: one cable for data and power
The Wi-Fi access point on the ceiling has one cable and no plug. That cable carries its power too.
1 min readExplainer
The short version
Power over Ethernet sends electricity and network data over the same cable, so access points, phones and cameras need no separate power outlet.
What it is
Power over Ethernet, or PoE, sends electrical power along a standard network cable together with the data. A device connected this way needs only one cable.
Where it is used
- Wi-Fi access points on ceilings and high walls, where there is no outlet.
- Desk phones, which then need no power adapter at the desk.
- Security cameras, indoors and out.
- Door access controllers, intercoms and some lighting and sensors.
How it is powered
Most often, the power comes from a PoE switch, a network switch that supplies power on some or all of its ports. For a single device, a small PoE injector can add power to one cable.
Things to plan for
- Power budget. A PoE switch can supply only so much power in total. Add up what your devices need, with room to grow.
- Device requirements. Newer access points and cameras may need a higher power standard than older switches provide.
- Battery backup. If the PoE switch is on a battery backup, phones and access points keep working during a short power cut. If it is not, they go down with it.
- Good cabling. Long or poor quality cables can cause problems with power as well as speed.
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